The invention relates to an air intake system, especially for use as an air intake duct of an internal combustion engine.
Air intake systems for internal combustion engines are provided with shunt resonators especially in the area of the intake tube in order to suppress the air intake noise. In the simplest case these shunt resonators consist of a resonator chamber and a resonator neck which connects the resonator chamber to the intake tube. This basic form of the shunt resonator can be varied according to the particular application. It is conceivable to have several necks which have different lengths to make it possible to dampen air intake noises of different frequencies. The resonator chamber can have almost any desired shape.
A disadvantage in the use of shunt resonators is the space they require in the area of the air intake tube. This must be provided in the motor compartment, which is difficult due to the restricted space in the motor compartment. An approach to the solution of the problem is to be found, for example, in DE 3842248 A1. A resonator is proposed which is integrated into the housing of the air intake system. In this manner it is possible to use the dead space present in the housing as a resonator chamber. Therefore there is no need to provide additional installation space in the motor compartment.
The above-described resonator chamber must, however, be given attention structurally when establishing the configuration of the intake tube housing. It is disadvantageous that the resonator described cannot be used to improve the acoustics of an existing intake tube if the results in regard to the intake noise of the intake tube are unsatisfactory. In such a situation there often is no more room in the motor compartment for a shunt resonator, since the development of the vehicle in question is nearly completed. Thus an expensive new design may be necessary in the intake tube area.